Method and machine for knitting tubular knitted articles

Abstract

The method provides for arranging a pick-up member for the tubular knitted article (M) coaxially with the needle cylinder, when knitting has been completed. The pick-up member (23) is provided with a plurality of pick-up hooks (25A, 25B) arranged according to a circular ring subdivided into two circular half-rings that can be overturned over each other. The tubular article is engaged by the pick-up hooks while the stitches of the last course of the knitted article are still held by the needles (5) of the knitting machine. The stitches of the last curse are then removed from the needles and the tubular article is removed from the needle cylinder (3) by means of the pick-up member (23). The two half-rings of pick-up hooks are overturned one onto the other, putting one of two opposite edges of the toe of the tubular article onto the other. The two edges are then sewn or linked.

Description

TECHNICAL FIELD[0001]The present invention relates to methods and machines for producing tubular knitted articles, such as socks and stockings.STATE OF THE ART[0002]For producing tubular articles, especially socks, circular knitting machines are used; these machines knit the article starting from an elastic border or edge up to an opposite end defining edge portions that, once sewn together, form the toe of the sock. In traditional machines, once the article has been knitted, the article is unloaded with the open toe, and the articles coming from one or more circular knitting machines are transferred to a sewing or linking machine or device. An operator picks up single articles, holding them at the toe end, and introduces them into the sewing machine or the linking machine to close the end of the toe. This traditional method is labor-consuming and therefore involves high production costs.[0003]Devices and circular knitting machines have been studied to automatically pick up the tubu...

AI Technical Summary

Benefits of technology

[0036]The opposite first and second edge portions of the toe can be joined by sewing. However, preferably the first and second edge portions of the open toe of the tubular knitted article are joined by linking. Linking differs from sewing in that in linking a closing stitch is formed at each pair of opposite stitches of the two edge portions, to join them. On the contrary, in sewing there is no correspondence between the stitches of the opposite first and second edge portions to join and the sewing stitches, thus obtaining a simpler process that however results in a less finished tubular article.

[0045]In some embodiments a step is provided for blocking the stitches engaged by the pick-up hooks by means of mechanical members, for instance in the form of closure latches, before the stitches of the last course are removed from the needles. In other embodiments the closure latches may be omitted and the stitches may engage in a reliable way to the pick-up hooks by forming the stitches at least in some of the last courses with an elastic yarn.

[0047]In some embodiments each pick-up hook and the respective closure latch can be co-planar. This arrangement results in small cross-sectional dimension of the hook-latch arrangement, so that the pick-up member can be used on knitting machines of high fineness, i.e. provided with a large number of knitting needles arranged relatively close to one another. In other embodiments each pair of pick-up hook and respective closure latch can be arranged side-by-side. This results in a more cumbersome but simpler to manufacture arrangement.

[0048]To make it easier for the pick-up hooks to pick the article up along the circular needle bed, in some embodiments the method may provide a step of raising or lifting the tubular article from a loop formation plane. Raising or lifting the article can be for instance by acting on the sinkers of the circular knitting machine. Alternatively, the tubular article can be lifted using an inner tube substantially coaxial with the needle cylinder. The tube is raised when knitting of the tubular article has been completed. The needles may be suitably extracted from the needle cylinder, i.e. raised, so that the stitches slide along the stems of the needles until they move beyond the needle latches. In this way it is possible, in a subsequent operating step, to unload the stitches by moving the needles back towards inside the tracks provided in the needle cylinder.

[0056]According to advantageous embodiments, the method of the present disclosure provides for producing at least one run-proof course before starting to remove the tubular article from the circular needle bed. This makes the engagement of the article by means of the pick-up hooks at one or more courses before the last one easier and safer.

[0057]In some embodiments, thanks to the novel method disclosed herein, there is no need for single pick-up elements, each of which co-acts with the corresponding needle of the cylinder, to remove the single stitches of the last course from the needles. It is therefore possible to handle the finished tubular article in a simpler and more reliable way, and to have a more robust machine, less subject to malfunctions or damages, without fragile and critical pick-up members typical of the known devices.

Problems solved by technology

This traditional method is labor-consuming and therefore involves high production costs.

The article thus obtained has high quality but the linking process is complex and long-lasting; furthermore the device for pick the tubular article up is particularly complex and expensive.

A very coarse and low-quality article of manufacture is obtained with this known device, which in addition generates a large amount of scraps.

Scraps are undesired, since they increase the overall manufacturing costs and generate waste which must be disposed of.

All these systems have inconveniences due to the complexity of the devices for handling the tubular knitted article or due to a low reliability.

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